The present invention relates to a starter apparatus for an internal combustion engine and particularly to a manually operated starter apparatus for a small engine forming a part of an outboard motor, a snowmobile, lawn mower, or recreational apparatus.
Internal combustion engines are conventionally started by positively initiating the rotation of the engine. An electric starter apparatus may be employed. Generally a suitable electric starter motor is coupled to a helix coupler which drives a pinion gear into engagement with a flywheel supported gear. Although such electric starter apparatus is widely employed, they do significantly increase the cost of the internal combustion engine mechanism. Consequently, manual starting apparatus is also widely employed, particularly for smaller engines. Outboard motors, snowmobiles and the like in particular may be constructed with relatively low horsepower drive means and employ corresponding small internal combustion engines housed within a decorative and protective cowl. Outboard motors of the order of four horsepower, for example, conveniently employ internal combustion engines which can be started by rotation of the engine through a manually operative rewind starter apparatus. Conventionally, the starter apparatus includes a spring-loaded, pull-rope driven mechanism coupled to the rotating drive means secured to the upper end of the engine such as the flywheel assembly for spinning of the engine. The operator manually, rapidly pulls the rope outwardly to turn the engine over during starting thereof. A suitable one-way drive system couples the rope mechanism to the engine to transmit the starting motion to the engine while automatically disengaging of the rope mechanism as the engine starts and the rotation of the crank and interconnected flywheel increases or becomes significantly more rapid than that of the rope activated mechanism. A coil spring unit is coupled to the rope driven mechanism to automatically rewind the rope, when released.
Although such systems are completely satisfactory, they do incorporate certain disadvantages, particularly when applied to outboard motors and the like. The mounting of the unit to the upper end of the engine requires increasing the overall height of the assembly and the outer protective cowling. Although such structure does not affect the operational characteristics of the engine, a minimum profile may be desired for esthetic purposes.
Further, the rope unit is normally exposed adjacent to the upper end of the engine with a resulting maximum tilt force on the motor assembly as such. The outboard motor is normally mounted to the transom by a suitable swivel bracket assembly located immediately beneath the powerhead unit. The top mounting of the rope produces a significant moment arm with respect to the swivel brackets which may result in tilting of the motor when starting. Although various guide arrangements can be provided to lower the point of force application relative to the swivel axis, such structure further increases the complexity of the starting mechanism as well as introducing possible points of failure. The top mounted starter units, further, are not particularly adapted to certain conventional small outboard motor applications such as larger sailboats. Conventionally, a sailboat of any significant size is provided with an auxiliary engine to permit movement in the event of wind failure or loss of sailing capability. In many larger sailboats, a small outboard motor is mounted within a well in the aft portion of the sailboat. The conventional outboard motor starter is not conveniently located for a vertical upward pull and thus is difficult to operate, or requires special adaptation of the well and/or rope guide mechanism.
Further, when the cowl is removed from the conventional top mounted assembly, the total starting mechanism and particularly gearing system is essentially completely exposed. This may create a possible dangerous environment if the operator or some equipment should engage the gears during motor starting.
Thus, although the conventional rewind starter mechanism and the like has been widely employed and produced satisfactory starting means, Applicant's analysis of such prior art systems has shown certain practical disadvantages.